Re: Re[PATCH v1] iommu: Skip mapping at address 0x0 if it already exists

[Thorsten Leemhuis]

On 4/5/26 17:02, Elisabetta Bruno wrote:
> On Sun, 22 Feb 2026 00:50:50 +0100 Antheas Kapenekakis <lkml@xxxxxxxxxxx> wrote:
>> Commit 789a5913b29c ("iommu/amd: Use the generic iommu page table")
>> introduces the shared iommu page table for AMD IOMMU. Some bioses
>> contain an identity mapping for address 0x0, which is not parsed
>> properly (e.g., certain Strix Halo devices). This causes the DMA
>> components of the device to fail to initialize (e.g., the NVMe SSD
>> controller), leading to a failed post.
> [...]
>> Closes: https://www.reddit.com/r/cachyos/comments/1r5sgr6/
>> freeze_on_boot_after_kernel_update_to_619_fixed/
>> Fixes: 789a5913b29c ("iommu/amd: Use the generic iommu page table")
>> Signed-off-by: Antheas Kapenekakis <lkml@xxxxxxxxxxx>
> 
> As I am seeing this still marked as pending fix, hopefully some real
> world testing might help.

I lost track here, but from a quick look I suspect 0a4d00e2e99a39
("iommu: Fix mapping check for 0x0 to avoid re-mapping it") [v7.0-rc5,
v6.19.10] fixed this;
https://lore.kernel.org/all/20260227080638.208693-1-lkml@xxxxxxxxxxx/
and the links there have more details.

And if I'm wrong, please yell!

Ciao, Thorsten